Ammonia synthesis for fertilizer production

ABSTRACT

A method for synthesizing ammonia for agricultural fertilizers employs water (H2O) as the source of hydrogen (H2) in ammonia (NH3) synthesis, and gathers carbon monoxide (CO) as a limiting reagent for combining in a WGS (Water-Gas-Shift) reaction for producing hydrogen. The WGS reaction employs CO with the water to produce Carbon Dioxide (CO2) and H2, consuming undesirable CO from other industrial applications. A by-product of the process includes generating 1.5 mole of CO2 for each mole of ammonia synthesized. An intermediate step consumes 3 moles of hydrogen for each mole of Nitrogen (N2). The use of methane gas is avoided as the process employs CO and the WGS reaction as an exclusive source of H2 without introducing methane (CH4). A downstream synthesis of ammonia can be done through a fuel cell to produce electricity for the ammonia synthesis for further sustainability.

RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119(e) of U.S.Provisional Patent Application No. 62/121,039, filed on Feb. 26, 2015,entitled “AMMONIA SYNTHESIS FOR FERTILIZER PRODUCTION,” incorporatedherein by reference in entirety.

BACKGROUND

The development of mass produced fertilizer revolutionized theindustrial agriculture industry by maximizing the crop yield that can begrown on a given parcel of land. Fertilizers, along with irrigationsystems to relieve dependence on natural precipitation, allow apredictable, optimal yield of agricultural stock from farmland.Fertilizer production employs substantial amounts of ammonia. In solidor liquid states, ammonia salts and solutions are the active componentsof most synthetic fertilizers used in agriculture, which consume 83% ofthe world's ammonia and warrant higher demands for ammonia production.The primary industrial method for ammonia synthesis is the Haber-Boschprocess, created by Fritz Haber in 1905 and developed for industry byCarl Bosch in 1910. The overall process synthesizes ammonia frommolecular nitrogen and hydrogen by feeding the reactants over ironcatalysts at a high pressure and temperature, requiring bulky,well-insulated reactors to house the process, and large quantities ofnatural gas.

The Haber process synthesizes approximately 150 million tons of ammoniaeach year and has allowed the earth to sustain a greatly increasedpopulation. However, the use of natural gas as a source of hydrogen andenergy needed to derive nitrogen from atmospheric air have been thesubjects of environmental concern. The industrial use and geologicalextraction of natural gas are known to contribute to carbon dioxideemissions and water pollution, respectively, and today an estimated 59%of natural gas produced in the United States is used in ammoniasynthesis to meet the high demand of gaseous hydrogen. Approximately 80%of ammonia synthesized today is eventually converted into ureafertilizer, a dense nitrate that is more stable at room temperature,allowing easier storage and transportation than ammonia.

SUMMARY

A method for synthesizing ammonia for agricultural fertilizers employswater (H₂O) as the source of hydrogen (H₂) in ammonia (NH₃) synthesis,and gathers carbon monoxide (CO) as a limiting reagent for combining ina WGS (Water-Gas-Shift) reaction for producing hydrogen. The WGSreaction employs CO with the water to produce Carbon Dioxide (CO₂) andH₂, consuming undesirable CO from other industrial applications. Aby-product of the process includes generating 1.5 mole of CO₂ for eachmole of ammonia synthesized. An intermediate step consumes 3 moles ofhydrogen for each mole of Nitrogen (N₂). The use of methane gas isavoided as the process employs CO and the WGS reaction as an exclusivesource of H₂ without introducing methane (CH₄). Methane production isexpensive and burdens the conventional approaches.

Configurations herein are based, in part, on the observation thatconventional approaches to ammonia synthesis for urea and fertilizerproduction employ a water-gas shift (WGS) with hydrogen H₂ and carbonmonoxide (CO). Unfortunately, conventional approaches suffer from theshortcoming that they tend to rely heavily on natural gas such asmethane as a source of hydrogen, resulting in a substantial discharge ofCO₂ as a byproduct. Accordingly, configurations herein substantiallyovercome the above-described shortcomings by employing only water as thehydrogen source for ammonia synthesis. The disclosed process employs theWGS reaction as the hydrogen producing step, and entails the use ofcarbon monoxide for producing the raw materials needed for hydrogenproduction as (CO+H₂O)→(CO₂+H₂). The limiting reagent in this process istherefore the CO. Different sources can be used for CO input such ascarbon black manufacturing, steel mills, electrical generation plants,or other industrial processes.

In conventional approaches, the processes by which ammonia and urea aresynthesized can be summarized as simplified stoichiometric equations:

Ammonia: N2+3H2←→2NH3

Then in another industrial location or plant:

Urea: 2NH3+CO2←→(NH2)2CO+H2O

Or 2NH3+1/2O₂+CO←→(NH2)2CO+H2O

Urea is significant because 80% of the ammonia manufactured todaybecomes feedstock for the manufacture of urea, a more stable nitrateused for fertilizer. However, the modern syntheses of ammonia and urearequire several necessary and costly processes and treatments to achievethe highest yield possible, which must be considered to accuratelyassess their effectiveness, as well as their impacts on the environmentand industry.

In further detail, the disclosed method for synthesizing ammoniaincludes receiving carbon monoxide (CO) from an industrial process, andproviding the received carbon monoxide to a hydrogen separator forreacting the carbon monoxide with water from a water source forproducing hydrogen (H₂). A mixer or other vessel combines the hydrogenwith nitrogen from a nitrogen reactor for synthesizing ammonia, suchthat the hydrogen is generated exclusively from the water provided tothe hydrogen separator, which avoids consumption of methane or othernatural gas in the ammonia production process.

The disclosed method may entail a system for synthesizing ammonia frombyproducts of industrial operations, including a scrubber and/ormembrane separator and/or ammine absorption for receiving exhaust fluegas, in which the exhaust includes carbon monoxide, and removes sulfurbased compounds from the exhaust. A CO mixer combines the scrubbedcarbon monoxide with water. A hydrogen separator has a membrane forseparating and passing purified hydrogen (H₂), and a hydrogen mixercombines the separated hydrogen with nitrogen. Finally, an ammoniareactor receives the hydrogen and nitrogen, and combines the hydrogenand nitrogen under applied heat and pressure for synthesizing ammonia,in which the hydrogen is sourced exclusively from the water passedthrough the hydrogen separator membrane and any residual hydrocarbonsfrom the exhaust flue gas, in contrast to conventional methane.

The system may be further enhanced by considering the downstreamsynthesis of urea using a PBI phosphoric acid fuel cell that usesammonia and purified carbon monoxide as anode fuel and oxygen from airin the cathode; this fuel cell is to produce urea, electricity andwater. It was suggested to use a PAFC at about 180 C and 30 bar. Underthese conditions, it was predicted that the fuel cell will have morethan 95% single pass yield, and an affiliated overall efficacy of 70% byrecycling raised steam through turbines. This employs the single stagesynthesis of urea illustrated in the second urea synthesis method above.The raised electricity from the fuel cell urea synthesis and waterproduction will contribute to supplying electricity to the ammoniasynthesis process making it even more sustainable and less reliant onfossil fuels.

It is suggested that through this design with an optimal CO and waterinput it is possible to have a urea manufacturing facility that onlyuses CO from flue gas, water and nitrogen and oxygen from air tosynthesize urea without the need for external electricity or steam orany other raw materials. It is also suggested to use other renewablesources of electricity such as solar panels and wind mills to supply theaccess need of electricity without external supply.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following description of particularembodiments of the invention, as illustrated in the accompanyingdrawings in which like reference characters refer to the same partsthroughout the different views. The drawings are not necessarily toscale, emphasis instead being placed upon illustrating the principles ofthe invention.

FIG. 1 is a diagram of an ammonia synthesis sequence as describedherein.

FIG. 2 shows a context diagram of an industrial environment suitable foruse with configurations depicting FIG. 1;

FIG. 3 shows a process flow of an ammonia and urea synthesis process ofFIG. 1 in the environment of FIG. 2;

FIG. 3a correlates pressure and temperatures of a production streamdepicted in FIG. 3;

FIG. 4 shows an alternate configuration for coupling thermal demands ofthe process of FIG. 3;

FIG. 5 shows an alternate configuration for a hydrogen separationmembrane as in FIG. 3;

FIG. 6 shows a flowchart of ammonia synthesis as in FIGS. 1-5; and

FIG. 7 shows synthesized ammonia of FIG. 5 in a fuel cell for poweringthe synthesized process.

DETAILED DESCRIPTION

Ammonia synthesis for fertilizer production has a significantenvironmental and atmospheric effect. The majority of greenhouse gasesemitted as a result of ammonia synthesis are released through thepreparation of hydrogen from the feedstock. A dramatic example would bethe ammonia manufacturing plants in China, 80% of which use coal asfeedstock as opposed to natural gas or naptha. Hydrogen is produced fromcoal through gasification (or partial oxidation), in which the coal isreacted with oxygen and steam at high temperatures and pressures. Thereaction produces a synthesis gas containing hydrogen and carbonmonoxide, the latter of which is reacted with excess hydrogen to formcarbon dioxide which can then be removed. While plants that use coal asfeedstock make up the minority of plants worldwide, China currentlyproduces more ammonia than any other country in the world. Of the 70million tons of ammonia produced in China annually, an estimated 80% issynthesized with hydrogen from coal—this accounts for a sizable fractionof the world's total ammonia production. For most plants worldwide,natural gas is much more affordable than coal or heavy oil as afeedstock, and natural gas is considered to be the most sustainable ofthese fuels. However, the use of a cleaner feedstock does not rendermanufacturers unable to release the same potentially harmful compounds.In processes using the catalytic steam forming of natural gas (the vastmajority of existing plants), carbon monoxide formed from the catalyticsteam reforming step is reacted with excess hydrogen to form carbonmonoxide, which is more easily removed from the system, similar to theprocess used for coal gasification. Through scrubbing, any residualcarbon dioxide can be heated and purged from the system, occasionallythrough vents releasing it into the atmosphere. Plants have designedmethods of capturing the carbon dioxide produced through steam forming,preventing the gas from entering the atmosphere and potentiallyrepurposing the compound by feeding it into another process in whichcarbon dioxide is a reactant. Considering the majority of ammonia isconverted to urea before it is used in fertilizers, it seems practicalfor carbon dioxide to be captured from steam forming and used as areactant in urea synthesis. However, many smaller ammonia plants andplants that operate independently of urea production simply vent thesefumes to the atmosphere, and even plants that recycle carbon dioxideemissions in the synthesis process where the gas is not as easilycaptured. The Intergovernmental Panel on Climate Change (IPCC) notesthat the only plants that do not release carbon dioxide during thesynthesis process are those that use a pure hydrogen feedstock ratherthan natural gas, which makes up a very marginal percentage of plants.

Various configurations depicting the above features and benefits asdisclosed herein are shown and described further below. Mitigation ofthe environmental effects of ammonia and urea synthesis are depicted inan example apparatus shown and disclosed below. Alternate approaches toembody the disclosed principles.

Conventional approaches for ammonia and urea synthesis employ thewell-known Haber process. This conventional approach uses methane gas(CH₄) and water (2H₂O) as the sources of hydrogen, giving off (CO₂,4H₂). However, methane can be expensive and limiting to the process. Italso produces one mole of CO₂ as a result of the production of one moleof ammonia (NH₃). Configurations herein employ only water (H₂O) for theammonia synthesis. This process will invoke the WGS reaction as thehydrogen producing step. This process will require the use of carbonmonoxide making the raw materials needed (CO+H₂O)→(CO₂+H₂). The limitingreagent in this process will be the CO. Rather than consuming naturalgas for a source of hydrogen, existing industrial sources can be usedfor CO input such as steel mills, different electricity generators . . .etc. The proposed ammonia synthesis process when compared to currentprocesses used doesn't by itself generate any carbon oxides. However,for every two moles of ammonia synthesizes three moles of carbonmonoxide is converted to a safer carbon oxide (carbon dioxide).

In an example configuration disclosed herein, it is proposed to have ahigh CO₂ concentration to favor the first reaction not raising pressureexcessively high. The overall combined factors in an industrial settingas described above result in a lower energy profile for the proposedoverall reaction:

3H₂O+3CO+N₂→(NH₂)₂CO+H₂O+2CO₂

RXN1: 3H₂O+3CO→3H₂+3CO₂

RXN2: N₂+3H₂→2NH₃

RXN3: 2NH₃+3CO₂→(NH₂)₂CO+H₂O+2CO₂

A further advantage over conventional approaches used for the synthesisof both ammonia and urea is the thermal coupling of the two reactions.In conventional approaches, almost 60% of the ammonia producedinternationally is converted to Urea. Configurations herein propose tohave both ammonia and urea synthesis in one factory as a thermocoupledprocess, or reaction. Taking note that the WGS reaction, ammoniareaction, and urea reaction are effectively exothermic reactions, itwould be beneficial to recover and redirect excess energy. Where the useof a fuel cell for the production of urea is suggested. A PAFC in a PBIarrangement is used at a temperature around 170 C and pressure of 45 baris initially suggested to give an overall process efficacy of 70%.Operating conditions such as minor temperature variation (160-200 C) andpressure of (45-200 bar) and necessary resonance time of the reductionof the ammonia R.NH₃ to R.NH₂ effectively with minor losses of ammoniato N₂ (lower than 5%). At that temperature, the water generated at thecathode side is at a useful temperature (160-200 C) where it goesthrough turbines to generate and recycle the most amount of energy. Theammonia fed to the anode is premixed with carbon monoxide at a 2:1ratio.

FIG. 1 is a diagram of an ammonia synthesis sequence as describedherein. Referring to FIG. 1. Referring to FIG. 1, the major componentsin the disclosed ammonia synthesis process include a scrubber and/ormembrane separator and or amine absorption 1001 for receiving industrialwaste gases (i.e. exhaust) and producing pure CO for use in ammoniasynthesis. A mixer 1002 combines heated water with the CO, and passes itto a WGS reactor 1003. The WGS reactor 1003 separates pure hydrogen H₂and emits only CO₂ and water as byproducts. Hydrogen generation may beaugmented as discussed further below. The purified hydrogen is passed toa second mixer 1004 for receiving nitrogen N₂ from a nitrogenseparator/generator 1005. Purified nitrogen is ideally extracted fromsurrounding ambient sources. An ammonia reactor 1006 receives thehydrogen and nitrogen for generating ammonia NH₃, and an ammoniaseparator 1007 separates the synthesized ammonia and recirculates thegases for resulting in a substantial ammonia yield of about 98%. Thepurified ammonia can then be passed to a urea plant 1008 for ureaproduction as used in fertilizer manufacturing or other industrial uses.

FIG. 2 shows a context diagram of an industrial environment suitable foruse with configurations depicting FIG. 1. FIG. 2 depicts one example ofan industrial environment for performing the processes of FIG. 1 whichattempts to arrange the steps of the ammonia synthesis in acomplementary manner. Configurations herein propose an efficient ammoniaand urea synthesis operation adapted to be implemented in an industrialsetting where waste, byproducts, and thermal energy given off orresulting from one industrial process are received and utilized inanother, to achieve as self-sustaining an operation as possible. Forexample, methane is an expensive hydrogen source, and imposessubstantial environmental impact, so configurations herein employ COfrom existing industrial combustion and water from a wastewater orindustrial source to generate hydrogen gas and a byproduct of carbondioxide (CO₂).

Referring to FIG. 2, a CO source 200 such as a factory or electricalplant emits exhaust including CO. The exhaust supply 202 is received bya scrubber and/or membrane and/or amine absorber 204 for separating COfrom sulfides and other exhaust components. The purified CO 206 iscombined with a water supply 208 in a hydrogen separator 210. The watermay be sourced from any suitable source, such as a waste product ofanother industrial cooling operation or pumped from a nearby repository212. A nitrogen separator 214 or nitrogen membrane provides nitrogenfrom ambient air sources, and combines the N₂ with the H₂ from thehydrogen separator 210 in an ammonia reactor 216. In contrast toconventional approaches, which inject substantial heat into the ammoniareactor 216, the ammonia reactor 216 may be disposed within and/orcoupled thermally to the hydrogen separator 210 for mitigating heatrequirements and/or may receive excess thermal energy 218 from the COsource 200. The thermal coupling 220, while not required, furtherreduces combustion required for ammonia production by utilizingbyproducts from the CO source. In an example configuration, the COsource 200 may be a carbon black manufacturing facility, discussedfurther below. Thermocoupling of related processes may also occurbetween the heated combination of CO and H₂O (206, 208) and the heatingof input to the hydrogen separator 210.

FIG. 3 shows a process flow of an ammonia and urea synthesis process ofFIG. 1 in the environment of FIG. 2. FIG. 3a correlates pressure andtemperatures of a production stream depicted in FIG. 3. Referring toFIGS. 2, 3 and 3 a, an example plant design uses a total of fivecompressors, six heat exchangers, four vessels, a hydrogen separator 210such as a water-gas shift (WGS) membrane, a nitrogen separator 214 ormembrane, and an ammonia reactor 216. FIG. 3a lists the approximate orexample physical properties of the referenced elements 1-27 for theexample configuration.

Initially, exhaust gas 1 from a carbon black refinery or manufacturingplant enters the scrubber 204 at a temperature and pressure of 25° C.and 1 ATM where the gas components are mixed with water 2 and the usefulCO is separated from contaminants 4, including sulfur dioxide (SO₂) andhydrogen sulfide (H₂S). Sulfur recovery may be performed using lime,precipitating the contaminant sulfur. Lime is a very inexpensivecompound, and the resulting solid can be repurposed as a filler incement production plants, for example.

Exiting the scrubber and membrane 204, the waste water stream ofsulfides in water can be saved and used for sulfur recovery. A productstream 3 containing CO is mixed in a vessel V-102 with fresh water 6 ata 2:1 molar ratio of water to CO. The water 5 is heated by heatexchanger HE-101 to combine with the CO, and is then heated to 450° C.by heat exchanger HE-102 and pressurized 8 by compressor C-101 inpreparation for hydrogen separation such as from the water-gas shiftreaction. Thermal coupling between HE-102 and HE-101 heating the feedwater 6 may result from a common source.

For the WGS reaction in the hydrogen separator 210, the heated stream ofwater and CO 9 enters the hydrogen separator 210, such as aniron-chromium catalyzed membrane 211 reactor. The hydrogen separator 210employs palladium plating to improve and promote proton transfer suchthat the separation reaction RXN1 (above) is undergone and pure hydrogen10 is separated and recovered while water and CO₂ in a 1:1 molar ratiodefine a purge stream 11 for venting CO₂ from the production stream.With the H₂ feedstock secured, a nitrogen membrane separator 214 is usedto isolate high-purity molecular N₂ 16 from the ambient air 12. Nitrogen14 is introduced by any suitable method, such as compressing the air 13at compressor C-102 and heating by heat exchanger HE-106.

H₂ gas is mixed with N₂ at a 3:1 molar ratio in vessel V-103, and thestream 17 pressurized 18 by compressor V-103, heated by heat exchangerHE-103 19 and pressurized to 450° C. and 200 bar 20 by compressor C-104,respectively, preparing the stream 20 for the ammonia synthesis reaction21. An ammonia reactor 216, operating at a high temperature and pressureand equipped with an iron-chromium catalyst 217, reacts the H₂ and N₂ 22and achieves a single-pass ammonia yield 23 of approximately 20-28%,though the product ammonia 23 is isolated using a membrane separator andheat exchanger HE-104 and the unreacted gases 24 are fed 25 bycompressor C-105 back into 26 the reactor 216 until a total yield ofapproximately 98% of the reactant gases have been reacted.

In the final steps of the disclosed process, the product ammonia 23(still at a high temperature and pressure) is mixed with excess CO₂produced in the carbon black refinery and reacted at a temperature andpressure of about 180° C. and 150 bar, respectively. This stream isintended to be reacted into urea, a common nitrate. For example, if thestream of NH₃ and CO₂ was used as the feedstock to a nearby ureasynthesis plant as disclosed in FIG. 7 below, such a coupling wouldeliminate or alleviate the need to heat and pressurize the stream beforesynthesis, and the CO₂ formed as a byproduct in the WGS reaction couldbe saved and fed into the process, both improving urea yield efficacyand preventing the emission of a greenhouse gas.

FIG. 4 shows an alternate configuration for coupling thermal demands ofthe process of FIG. 3. Referring to FIGS. 3 and 4, and as alluded abovewith respect to thermocoupling the different steps, the approach of FIG.4 couples thermal inputs of the carbon monoxide scrubber 204 and thehydrogen separation. FIG. 4 illustrates supporting the ammonia reactor216 with heat from the hydrogen separator and WGS reactions,specifically by disposing an ammonia reactor within the hydrogenseparator environment, thus directing heat from the hydrogen separatorto an ammonia reactor for synthesizing the ammonia. Other forms ofthermal coupling may be performed, however.

This proposed approach is intended to take place within a pipe 400 orother containment that houses a smaller reactor 410. In this process, awater-gas shift reaction 402 is catalyzed on the outside 404 of thereactor 410, providing heat and hydrogen feedstock for the ammoniasynthesis reaction housed within the reactor 410. Nitrogen input 16 isprovided externally to combine with H₂ resulting from the hydrogenseparation, and the resulting NH₃ yielded. This combined process, whenoperated for commercial ammonia production, makes use of an ironcatalyst for the WGS reaction and ammonia synthesis reaction, as well aspalladium for increased proton transfer.

FIG. 5 shows an alternate configuration for a hydrogen separationmembrane as in FIG. 3. The configuration of FIG. 5 aims to replace themembranes needed in the hydrogen separator with a centrifugal membrane500. This process is designed to centrifugally separate gases in themembrane. With the use of a palladium-silver membrane 510 for improvedhydrogen separation, a centripetal feed forces the gases to separate inorder of density, as shown by layering 520, effectively isolating astream of hydrogen (the lightest molecule present) while forcing heaviermolecules through the membrane. This results in a boundary layer of purehydrogen surrounding the membrane. Such a centrifugal membrane 500provides better yields than the traditional feedstock of mixed H₂ andN₂. The flux achieved with a feed of pure hydrogen, separated by acentrifugal membrane, increases hydrogen yield

The gases being forced through the membrane are contained in a wasterecovery system while the hydrogen stream is fed through a compressor orheat exchanger, then into an ammonia reactor. If developed forcommercial use, this centrifugal membrane process could replace the N₂membranes used in current ammonia synthesis, reducing the plant'scapital cost while operating at up to 600% efficacy.

FIG. 6 shows a flowchart of ammonia synthesis as in FIGS. 1-5. Referringto FIGS. 1-6, the method for synthesizing ammonia, as disclosed hereinincludes, at step 600, receiving carbon monoxide (CO) from an industrialprocess. In an example configuration, the CO is received from a carbonblack refining operation, by capturing exhaust gases from the carbonblack refining, and passing the captured exhaust gases through ascrubber 204 or other process for separating sulfides, as depicted atstep 601. The disclosed approach strives to utilize and repurpose thebyproducts from other industrial processes. This process synthesizesammonia from exhaust gas leaving a carbon black refinery, using liquidwater and atmospheric air as sources for molecular hydrogen andnitrogen, respectively.

Carbon black possesses a range of unique properties that have made itdesirable for a variety of applications. Today, the carbon compound isused most commonly as a reinforcing agent in plastic and rubberproducts, as pigment in paints and inks, and occasionally as automobileand aerospace coating, due to the improved conductivity and UVprotection provided by the compound. In the United States, 90% of carbonblack is manufactured through an oil furnace process in which a liquidhydrocarbon is heated, continuously pumped into the combustion zone of anatural gas furnace and quickly cooled, ultimately producing carbonblack through the incomplete combustion of the feedstock hydrocarbon. 20The exhaust gas from this process contains mostly CO with variableconcentrations of sulfides SO₂ and H₂S, and is fed into a scrubber wherethe exhaust contaminants are mixed with water and dissolved CO isseparated from the mix.

The process provides the received carbon monoxide to a hydrogenseparator 210 for reacting the carbon monoxide with water from a watersource 212 for producing hydrogen (H₂), as disclosed at step 602. Thehydrogen separator 210 is a catalyzed membrane reactor having apalladium membrane, which is further operable for passing the hydrogenthrough the palladium membrane, as depicted at step 603.

From the hydrogen separator 210, the process combines the hydrogen withnitrogen from a nitrogen reactor 214 for synthesizing ammonia, such thatthe hydrogen is generated exclusively from the water provided to thehydrogen separator 210, in contrast to conventional approaches, whichutilize natural gas as the source of hydrogen. In the examplearrangement, combining the hydrogen further includes combining thehydrogen with nitrogen in the ammonia reactor 216 at a 3:1 molar ratio,heating and pressurizing the combined hydrogen and nitrogen for passingresulting ammonia (NH₃) through a membrane for separating ammonia, andrecirculating the hydrogen and nitrogen for additional passes, each passyielding separated ammonia.

FIG. 7 shows synthesized ammonia of FIG. 5 in a fuel cell for poweringthe synthesized process. Referring to FIGS. 5 and 7, a module 700 for afuel cell is proposed using carbon monoxide CO and ammonia NH₃ as fuel702. The overall reaction is:

$\left. {{\frac{1}{2}O_{2}} + {2{NH}_{3}} + {CO}}\leftrightarrow{{{CO}\left( {NH}_{2} \right)}_{2} + {H_{2}O}} \right.$

The module 700 depicts production of urea and electricity using a fuelcell; this approach utilizes electro chemistry in the production asshown by the proton transfer of arrow 710. Since urea is a solid withtemperatures below 140 C, and considering the product of the fuel cellwill be urea in the case of ammonia fuel with carbon monoxide and usinga proton exchange module, a Phosphoric Acid Fuel Cell (PAFC) type ofchemistry is applicable.

The fuel cell module 700 depicts an electrochemical approach forsynthesizing urea from carbon monoxide and ammonia to allow the processto produce electricity as well as urea. The module 700 receives thesynthesized ammonia, in which the module has an electrolyte 712, aseparator 714, and terminals 716, 718 on opposed sides of the separator.The module 700 converts the received ammonia into urea, such that theconversion results in an ionic flow across the separator 714 forgenerating a voltage differential between the opposed terminals 716,718. The generated voltage can be employed elsewhere in the ammoniaand/or urea synthesis, such as for operating compressors, pumps or heatexchangers. The electrochemical approach of the synthesis of urea willreplace the reactor 820 with a PAFC or a PBI fuel cell such as themodule 700. PBIs are pipes membranes that serve the commercialelectrochemical synthesis.

While the system and methods defined herein have been particularly shownand described with references to embodiments thereof, it will beunderstood by those skilled in the art that various changes in form anddetails may be made therein without departing from the scope of theinvention encompassed by the appended claims.

What is claimed is:
 1. A method for synthesizing ammonia, comprising:receiving carbon monoxide (CO) from an industrial process; providing thereceived carbon monoxide to a hydrogen separator for reacting the carbonmonoxide with water from a water source for producing hydrogen (H₂);combining the hydrogen with nitrogen from a nitrogen reactor forsynthesizing ammonia, the hydrogen generated exclusively from the waterprovided to the hydrogen separator.
 2. The method of claim 1 wherein thehydrogen separator is a catalyzed membrane reactor having a palladiummembrane, further comprising passing the hydrogen through the palladiummembrane.
 3. The method of claim 2 wherein combining the hydrogenfurther comprises combining the hydrogen with nitrogen in an ammoniareactor at a 3:1 molar ratio, heating and pressurizing the combinedhydrogen and nitrogen for passing resulting ammonia (NH₃) through amembrane for separating ammonia, and recirculating the hydrogen andnitrogen for additional passes, each pass yielding separated ammonia. 4.The method of claim 3 wherein the CO is reacted with the water at amolar ratio of substantially around 2:1 at a temperature of 450° C., andthe hydrogen and nitrogen is combined at 450° C. and at a pressure of200 bar.
 5. The method of claim 2 further comprising reacting thehydrogen and nitrogen in an ammonia reactor using an iron-chromiumcatalyst.
 6. The method of claim 1 further comprising receiving the COfrom a carbon black refining operation, by capturing exhaust gases fromthe carbon black refining and passing the captured exhaust gases througha scrubber for separating sulfides as well as other sources such assteel mills and electricity plants.
 7. The method of claim 6 furthercomprising coupling thermal inputs of the carbon monoxide scrubber andthe hydrogen separation for facilitating a self-sustaining electricalgeneration.
 8. The method of claim 2 further comprising directing heatfrom the hydrogen separator to an ammonia reactor for synthesizing theammonia.
 9. The method of claim 8 further comprising providing heat viaa thermal conduit from an industrial combustion process, the thermalconduit responsive to thermal energy vented as a byproduct from theindustrial combustion process for providing heat to the hydrogenseparator.
 10. The method of claim 3 further comprising: receiving thesynthesized ammonia into a module, the module having an electrolyte, aseparator, and terminals on opposed sides of the separator; andconverting the received ammonia into urea, the conversion resulting inan ionic flow across the separator for generating a voltage differentialbetween the opposed terminals.
 11. A system for synthesizing ammoniafrom byproducts of industrial operations, comprising: a scrubber and/ormembrane for receiving exhaust, the exhaust including carbon monoxide,and operative to remove sulfur based compounds from the exhaust; a COmixer in communication with the scrubber for combining the scrubbedcarbon monoxide with water; a hydrogen separator for receiving thecarbon monoxide and water, the hydrogen separator having a membrane forseparating and passing purified hydrogen (H₂); a hydrogen mixer forcombining the separated hydrogen with nitrogen; and an ammonia reactorfor receiving the hydrogen and nitrogen, and combining the hydrogen andnitrogen under applied heat and pressure for synthesizing ammonia, thehydrogen sourced exclusively from the water passed through the hydrogenseparator membrane.
 12. The system of claim 11 wherein the hydrogenseparator is a catalyzed membrane reactor having a palladium membrane,further comprising passing the hydrogen through the palladium membrane.13. The system of claim 12 wherein the CO is reacted with the water at amolar ratio of 2:1 at a temperature of 450o C, and the hydrogen andnitrogen is combined at 450° C. and at a pressure of 200 bar, theammonia reactor responsive to combining the hydrogen further comprisescombining the hydrogen with nitrogen in an ammonia reactor at a 3:1molar ratio, heating and pressurizing the combined hydrogen and nitrogenfor passing resulting ammonia (NH₃) through a membrane for separatingammonia, and recirculating the hydrogen for additional passes, each passyielding separated ammonia.
 14. The system of claim 13 furthercomprising an iron-chromium catalyst in the ammonia reactor, theiron-chromium catalyst responsive to reacting the hydrogen and nitrogen.15. The system of claim 11 further comprising an exhaust flow from acarbon black refining operation, the hydrogen separator configured tocapture exhaust gases from the carbon black refining and passing thecaptured exhaust gases through a scrubber and/or membrane for separatingsulfides from the CO.
 16. The system of claim 15 further comprising athermocouple for coupling thermal inputs of the carbon monoxide scrubberand the hydrogen separation.
 17. The system of claim 15 furthercomprising a thermal conduit from the carbon black refining process, thethermal conduit responsive to thermal energy vented as a byproduct fromthe carbon black process for providing heat to the hydrogen separator,the thermal conduit further configured for directing heat from thehydrogen separator to an ammonia reactor for synthesizing the ammonia.18. The system of claim 11 further comprising: an electrical module forreceiving the synthesized ammonia, the electrical module having anelectrolyte, a separator, and terminals on opposed sides of theseparator, the ammonia reactor disposed in the module and configured toconvert the received ammonia into urea, the conversion resulting in anionic flow across the separator for generating a voltage differentialbetween the opposed terminals.
 19. A hydrogen separator device forsupporting an ammonia reactor, comprising: a scrubber and or membranefor receiving exhaust, the exhaust including carbon monoxide, andremoving sulfur based compounds from the exhaust; a CO mixer forcombining the scrubbed carbon monoxide with water; a hydrogen separatorhaving a membrane for separating and passing purified hydrogen (H₂); ahydrogen mixer for combining the separated hydrogen with nitrogen; anammonia reactor for receiving the hydrogen and nitrogen, and combiningthe hydrogen and nitrogen under applied heat and pressure forsynthesizing ammonia, the hydrogen sourced exclusively from the waterpassed through the hydrogen separator membrane; and a conduit to acarbon black refining operation, the conduit for capturing exhaust gasesfrom the carbon black refining and passing the captured exhaust gasesthrough a scrubber and or membrane for separating sulfides from the CO.20. The device of claim 19 further comprising a nitrogen reactorresponsive to the hydrogen for combining the hydrogen with nitrogen at a3:1 molar ratio, heating and pressurizing the combined hydrogen andnitrogen for passing resulting ammonia (NH₃) through a membrane or akettle condenser for separating ammonia, and recirculating the hydrogenfor additional passes, each pass yielding separated ammonia.